﻿/*
    Write a program that calculates n! / k! for given n and k (1 < k < n < 100).
    Use only one loop.
 */
using System;
using System.Numerics;

class NFactDivideKFact
{
    private static BigInteger Factoriel(BigInteger n)
    {
        BigInteger factN = 1;
        while (n > 1)
        {
            factN = factN * (n);
            n = n - 1;
        }
        return factN;
    }
    static void Main()
    {
        BigInteger n = BigInteger.Parse(Console.ReadLine());
        BigInteger k = BigInteger.Parse(Console.ReadLine());
        Console.WriteLine(Factoriel(n) / Factoriel(k));
    }
}
